Abstract Introduction Lung ultrasound (LUS) has a high diagnostic accuracy for identifying frequent conditions in the post-operative phase after lung transplantation (LTx). This study aimed to investigate the feasibility and clinical ability of LUS to identify pulmonary complications such as pleural effusions and pneumonias in the early postoperative phase after LTx. Methods A prospective cohort study of lung transplant recipients who consecutively underwent single LTx (SLTx) or double LTx (DLTx) at the National Lung Transplantation Center in Denmark from May 1 to October 31, 2015 was conducted. LUS was performed at four time points corresponding to post-transplant day 3, and weeks 2, 6, and 12 (LUS #1–4) to detect and monitor variation in pathological LUS findings over time. Concurrent with LUS #4, a high-resolution computed tomography examination of the thorax (HRCT) was also performed. Results 14 patients (1 SLTx/13 DLTx, 7 (50 %) women, mean age: 50.4 years) who had undergone the four prespecified LUS examinations were included. Pleural effusion was the most common condition and most pronounced at post-LTx week 2. Findings consistent with pneumonia increased during week 2 and subsequently decreased. Corresponding to LUS #1, 2, 3, and 4, pleural effusion occurred in 85.7 %, 92.9 %, 85.7 %, and 78.6 %, and pneumonia in 21.4 %, 28.6 %, 14.3 %, and 14.3 %, respectively. HRCT findings at post-LTx week 12 were predominantly presented by unspecific ground glass opacities. Conclusion In a post-LTx setting, LUS represents a clinical novelty as a feasible diagnostic and monitoring tool to identify pathological pulmonary complications in the early post-operative phase.